ISSN:
1399-3054
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Biology
Notes:
Boraginaceae seeds are particularly rich in Γ-linolenic acid (6,9,12-octadecatrienoic acid, Γ-18:3). In microsomes, the analysis of phosphatidylcholine (PC) molecular species by HPLC led to identification of 15 different molecular species; among them 4 contained Γ-18:3, mostly at position 2 of sn-glycerol. Time courses of acylation and desaturation in PC molecular species were examined when [14C]oleoyl-CoA or [14C]linoleoyl-CoA was provided as substrates to isolated microsomes. With [14C]oleoyl-CoA or [14C]linoleoyl-CoA and in the absence of NADH, 3 main labelled PC molecular species were found: 18:2/[14C]18:1, 16:0/[14C]18:1 and 18:1/[14C]18:1. When NADH was present in the incubation medium, the fatty acids were progressively desaturated by the Δ12- and Δ6-desaturases successively (with [14C]oleoyl-CoA as precursor) or by the Δ6-desaturase alone (with [14C]linoleoyl-CoA as precursor). In both types of experiments, 7 final desaturation products in microsomes were evidenced; among them, 3 contained radioactive Γ-18:3, i.e. 18:2/[14C]Γ-18:3, 18:1/[14C]Γ-18:3 and 16:0/[14C]Γ-18:3. While the Δ12-desaturase had no specificity for position on the glycerol backbone, labelled Γ-linolenic acid was recovered exclusively in the sn-2 position.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1034/j.1399-3054.2000.108002118.x
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